In a typical cellular radio system, wireless terminals (also known as mobile stations and/or user equipment units (UEs)) communicate via a radio access network (RAN) to one or more core networks. The radio access network (RAN) covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g., a radio base station (RBS), which in some networks may also be called, for example, a “NodeB” (UMTS) or “eNodeB” (LTE). A cell is a geographical area where radio coverage is provided by the radio base station equipment at a base station site. Each cell is identified by an identity within the local radio area, which is broadcast in the cell. The base stations communicate over the air interface operating on radio frequencies with the user equipment units (UE) within range of the base stations.
In some versions of a radio access network, several base stations are typically connected (e.g., by landlines or microwave) to a controller node (such as a radio network controller (RNC) or a base station controller (BSC)) which supervises and coordinates various activities of the plural base stations connected thereto. The radio network controllers are typically connected to one or more core networks.
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile communication system, which evolved from the second generation (2G) Global System for Mobile Communications (GSM). UTRAN is essentially a radio access network using wideband code division multiple access for user equipment units (UEs). In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for third generation networks and UTRAN specifically, and investigate enhanced data rate and radio capacity. Specifications for the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) are ongoing within the 3rd Generation Partnership Project (3GPP). The Evolved Universal Terrestrial Radio Access Network (E-UTRAN) comprises the Long Term Evolution (LTE) and System Architecture Evolution (SAE). Long Term Evolution (LTE) is a variant of a 3GPP radio access technology wherein the radio base station nodes are connected to a core network (via Serving Gateways, or SGWs) rather than to radio network controller (RNC) nodes. In general, in LTE the functions of a radio network controller (RNC) node are distributed between the radio base stations nodes (eNodeB's in LTE) and SGWs. As such, the radio access network (RAN) of an LTE system has an essentially “flat” architecture comprising radio base station nodes without reporting to radio network controller (RNC) nodes.
Changes in a wireless environment affect the quality of signal transmitted and received. Reception power rapidly decreases in proportion to increasing distance between wireless communication entities. As a result, a wireless communication system may employ a relay or repeater station (RS), a micro/pico base station, or a femto or home base station to expand coverage and/or improve throughput, quality, etc.
A repeater station is typically less sophisticated, expensive, and intelligent than a regular base station (BS), NodeB, eNodeB, or access point (AP). A relay station may perform the same functions as a base station except that a relay does not connect to the backhaul network with a cable or microwave link and instead uses a nearby macro base station to connect to the backhaul network. Both a repeater and a relay perform an “amplify and forward” (AF) function where it amplifies a signal received from a BS/AP or a MS/UE and delivers the amplified signal to the MS/UE or the BS/AP. Some relays may perform a decoding and forward (DF) function as well as a scheduling function where communicated information is restored by performing demodulation and decoding on a signal received from the BS/AP or the MS/UE and generating the restored signal by performing coding and modulation which is then sent to the MS/UE or the BS/AP. Any cellular radio access node that performs this “amplify and forward” (AF) function where it amplifies a signal received from a cellular radio network or a MS/UE and delivers the amplified signal to the MS/UE or the cellular radio network is encompassed by the term “cellular radio access node.” This includes relays, repeaters, traditional base stations and access points along with femto or home base stations that are not directly coupled to the radio access/backhaul network but instead communicate with the radio access/backhaul network via at least one other base station.
The cellular radio access node transmits or receives data using radio resources including one or more of a time resource, a frequency resource, a spatial resource, etc. The time resource may be expressed by a subframe, a symbol, a slot, etc. The frequency resource may be expressed by a subcarrier, a resource block, a component carrier, etc. The spatial resource may be expressed by spatial multiplexing, an antenna, etc. Such radio resources may be used in a dedicated or shared manner.
Certain cellular radio access nodes like repeaters and relays are not equipped to communicate directly with an operation and maintenance node for the communications system, and thus, do not send fault/ alarm data or performance monitoring data directly to operation and maintenance node. As a result, operation and maintenance of certain cellular radio access nodes like repeaters and relays is typically performed by technicians visiting the node site. This is expensive and time consuming. With increasing use of smaller nodes like relays and repeaters in communications networks deployed on a relatively large scale, the cost and time for such site visits also increases. Even where a malfunction is detected, it is not always apparent which relay or repeater is malfunctioning if there are multiple relays or repeaters operating in the same area.
Another problem is that between site visits, which may well be infrequent or in the case of relay, repeater, and small base station nodes rarely or non-existent, the network operator may not be made aware either in a timely fashion or ever of that such a node has malfunctioned or is operating below a certain performance level. As a result, it can take a long time before the operator discovers that the reason for a poor “dropped call rate” in an area is due to high noise level in a relay, repeater, or small base station.